BET surface area has been determined for 3% and 10% Ni catalyst on thoria modified silica support. The Th/Si mole ratios are 0, 0.0036, 0.0061, 0.0154, 0.031, 0.049 and 0.071. The BET area is calculated from nitrogen desorption method using a mixture of 30% nitrogen and 70% helium as a carrier gas in thermal conductivity detector of a gas chromatograph. The BET area of pure dried support is 239 m2/g and that of thoria modified dried support ranges from 226 m2/g to 167 m2/g. The calcined ThO2/SiO2 support gives BET area from 231 m2/g to 181 m2/g. In 3% Ni loaded support the area ranges from 222 m2/g to 164 m2/g while in 10% Ni loaded support the area decreases from 208 to 156 m2/g. 3% loaded Ni is a better catalyst.